SOLUTION: In problems on the model of one already solved -- Car rental agency A will rent a compact car for $40 per day and an additional charge of $0.20 per mile. Car rental agency B will c

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Question 207578: In problems on the model of one already solved -- Car rental agency A will rent a compact car for $40 per day and an additional charge of $0.20 per mile. Car rental agency B will charge only $0.16 per mile but charges $51 per day. If Adam wanted to rent a car for four days, how many miles would Adam have to drive to make car rental agency B a better bargain -- in which one is trying to figure when two terms calculated according to different rates of change reach equilibrium, why does the variable not go in the denominator? E.g., in this problem, ".20x" and ".16x" represent $.20/mile and $.16/mile.
Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website!
Car rental agency A will rent a compact car for $40 per day and an additional
charge of $0.20 per mile. Car rental agency B will charge only $0.16 per mile
but charges $51 per day. If Adam wanted to rent a car for four days, how many
miles would Adam have to drive to make car rental agency B a better bargain -
:
Let x = no. of miles driven for Agency B a better deal than A agency
:
Agency A 4-day cost greater than Agency B 4-day cost
.20x + 4(40) > .16x + 4(51)
:
.20x + 160 > .16x + 204
:
.20x - .16x > 204 - 160
:
.04x > 44
x >
x > 1100 mi
:
We can say that when the mileage exceeds 1100, B is cheaper than A
:
Let's say he drives 1101 mi
A: .20(1101) + 160 = 380.20
B: .16(1101) + 204 = 380.16; 4 cents cheaper
;
:
Answer to the question,"why does the variable not go in the denominator?"
You have to multiply the number of miles by the cost per mile, Right?
:
A mileage cost: 1100 * .20 = $220
:
"/" just per means "per" in this case, not divide.